Expandable mouth catheter

ABSTRACT

A catheter system that is actuatable to a deployed state and includes a catheter body and a dilator positioned at least partially within the lumen of the catheter. A distal end of the dilator can be releasably connected to a distal tip of the catheter body. The dilator can be retractable to expand and invert the distal tip and form a funnel shape in the deployed state.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional 62/898,864,filed Sep. 11, 2019, the contents which are herein incorporated byreference.

FIELD

The present disclosure generally relates to devices and methods forremoving acute blockages from blood vessels during intravascular medicaltreatments. More specifically, the present disclosure relates to anexpandable catheter used in aspiration of clots.

BACKGROUND

Clot retrieval catheters and devices are used in mechanical thrombectomyfor endovascular intervention, often in cases where patients aresuffering from conditions such as acute ischemic stroke (AIS),myocardial infarction (MI), and pulmonary embolism (PE). Accessingremote areas such as the neurovascular bed is challenging withconventional technology, as the target vessels are small in diameter,distant relative to the site of insertion, and are highly tortuous.

The clot itself can complicate procedures by taking on a number ofcomplex morphologies and consistencies, ranging from simple tube-shapedstructures which assume the shape of the vessel to long, strand-likearrangements that can span multiple vessels at one time. The age of aclot can also affect its compliance, with older clots tending to be lesscompressible than fresh clots. Fibrin rich clots also present achallenge in having a sticky nature that can cause a clot to roll alongthe outer surface of a mechanical thrombectomy device rather than beinggripped effectively. Combinations of soft and firm clot regions can alsoseparate during aspiration, with fragmentation leading to distalembolization which can occur in vessels that cannot be reached withcurrently available devices. Additionally, breaking the bonds adheringthe clot to the vessel wall without damaging fragile vessels is asignificant challenge.

Conventional clot retrieval catheters, especially those for operating inthe neurovascular, can suffer from a number of drawbacks. First, thediameters of the catheters themselves must be small enough to avoidcausing significant discomfort to the patient. The catheter must also besufficiently flexible to navigate the vasculature and endure highstrains, while also having the axial stiffness to offer smoothadvancement along the route. Once at the target site, typical objects tobe retrieved from the body can be substantially larger in size than thecatheter tip, making it more difficult to retrieve objects into the tip.For example, fibrin-rich clots can often be difficult to extract as theycan become lodged in the tip of traditional fixed-mouth catheters. Thislodging can cause softer portions of the clot to shear away from thefirmer regions, leading to distal embolization.

Small diameters and fixed tip sizes can also be less efficient atdirecting the aspiration necessary to remove blood and thrombus materialduring the procedure. The aspiration suction must be strong enough suchthat any fragmentation occurring through the use of a mechanicalthrombectomy device or other methods can, at the very least, be heldstationary so that fragments cannot migrate and occlude distal vessels.When aspirating with a traditional fixed-mouth catheter, however, asignificant portion of the aspiration flow ends up coming from vesselfluid proximal to the tip of the catheter where there is no clot. Thissignificantly reduces aspiration efficiency, lowering the success rateof clot removal.

The disclosed design is aimed at providing an improved aspiratingretrieval catheter which addresses the above-stated deficiencies.

SUMMARY

It is an object of the present design to provide systems, devices, andmethods to meet the above-stated needs. The design features anexpandable catheter with an expandable clot-facing mouth for flowrestriction, aspiration efficiency, and easy retrieval of the clot whilealso having a collapsed state that is low-profile and sufficientlyflexible for delivery in a standard sheath or outer catheter. Thecatheter can also have a tailored, variable-stiffness body sectionincorporating deliverability enhancements over existing designs andcapable of navigating tortuous areas of the vasculature to reach anocclusive clot.

In some examples, a catheter system is disclosed that is actuatable to adeployed state. The system can include a catheter body with a lumen. Adilator can be positioned at least partially within the lumen, a distalend of the dilator being connected to a distal tip of the catheter body.The dilator can be retractable to expand and invert the distal tip toform a funnel shape in the deployed state.

In some examples, the distal tip can include a proximal segment and adistal segment extended from the proximal segment and beingsubstantially flexible. A proximal end of the distal segment can beextended from the proximal segment and can include a pull ring adjacentand/or connected to a distal end of the distal segment.

In some examples, a midpoint of the distal segment in a collapsed statetransitions to being a distalmost atraumatic end of the funnel shape inthe deployed state distal of the catheter body.

In some examples, the distal segment in a collapsed state can besubstantially tubular and in the deployed state can include the funnelshape. An air cushion can be formed by the funnel shape between thedistal end and the pull ring.

In some examples, the distal segment can be divided into a proximalbraid portion and a distal spiral portion.

In some examples, the dilator can include a proximal segment and adistal segment distal of the proximal segment can include a diametergreater than the proximal segment, the distal segment can include acontact element extended radially outward from the distal segment of thedilator and configured to contact and translate proximally the pull ringuntil being aligned at or adjacent the proximal end of the distalsegment of the dilator.

In some examples, the contact element can include an interference fitwith the distal end of the distal tip of the catheter body.

In some examples, the distal segment of the dilator can include agreatest diameter at the contact element and decreases from the contactelement to the distal end of the distal segment.

In some examples, the distal segment of the dilator can include agreatest diameter at the contact element and tapers from the contactelement to a junction between the proximal and distal segments of thedilator.

In some examples, the proximal segment of the dilator being highlyflexible or substantially more flexible than the distal segment of thedilator.

In some examples, the dilator can include a substantially flexiblesegment extending distally of the stiffer distal segment, thesubstantially flexible segment being a short nose.

In some examples, the proximal segment of the dilator can include afiber reinforcement system to negate elongation.

In some examples, the dilator can include a proximal segment and adistal segment distal of the proximal segment. The distal segment of thedilator can include a greatest diameter greater than the proximalsegment. The distal segment of the dilator can include a distal contactelement extended radially outward from the distal segment and configuredto contact and translate proximally the pull ring until being aligned ator adjacent the proximal end of the distal segment. A proximal contactelement of the dilator can be proximally spaced from the distal contactelement and extended radially outward from the distal segment andconfigured to contact and translate proximally the pull ring, theproximal contact element can include a diameter less than the distalcontact element. The pull ring can be connected between the contactelements.

In some examples, the pull ring can be positioned in a gap positionedbetween the contact elements.

In some examples, the contact element can include an interference fitwith the distal end of the distal tip when in the funnel shape of thedeployed state.

In some examples, at least one of the contact elements includes amagnetic connector operable to magnetically retract the distal tip tothe funnel shape of the deployed state.

In some examples, the proximal segment and/or the distal segment of thedilator can include a substantially thinned wall.

In some examples, the proximal segment can include string-like filamentsconfigured to prevent elongation under tension.

In some examples, the proximal segment of the distal tip can be stifferthan the distal segment.

In some examples, the distal segment can be stiffer than the proximalsegment.

In some examples, the distal segment can include a resistance to remainin a substantially tubular shape prior to deployment.

In some examples, the proximal segment and/or the distal segment of thedistal tip can include a braided structure.

In some examples, the proximal segment and/or the distal segment of thedistal tip can include a memory alloy.

In some examples, the distal segment of the distal tip in a collapsedstate can be substantially tubular and in the deployed state can includethe funnel shape, an air cushion formed by the funnel shape between thedistal end and the pull ring.

In some examples, the dilator can include a proximal segment and adistal segment distal of the proximal segment. The distal segment caninclude a distal contact element extended radially outward from thedistal segment and configured to contact and translate proximally thepull ring until being aligned at or adjacent the proximal end of thedistal segment of the distal tip. The pull ring can include a magneticconnector. The proximal end of the distal tip is magnetized configuredto attract the pull ring thereby causing the distal tip to retract tothe funnel shape.

In some examples, the proximal end of the distal tip and the pull ringare locked together in the deployed state, including, but not limitedto, corresponding magnets locked together.

In some examples, the proximal end of the distal tip and the pull ringeach include planar mating surfaces.

In some examples, the proximal end of the distal tip and the pull ringeach include mating surfaces profiled with ridges and/or interlockingrecesses.

In some examples, the proximal end of the distal tip and the pull ringeach include mating surfaces tapered for a taper lock interaction.

In some examples, the proximal end of the distal tip and the pull ringeach include mating surfaces configured to snap lock together.

In some examples, the pull ring includes a similar diameter to thecatheter body such that an abutment is formed between the pull ring andcatheter body in the deployed state. The distal tip can extend distallyfrom an inner diameter of the pull ring and around an outer diameter ofthe pull ring to extend proximally over the catheter body.

In some examples, the distal tip can include a proximal segment and adistal segment extended from the proximal segment. The distal segment ofthe distal tip can be substantially flexible and include a proximal endpositioned on an outer surface of the distal tip. The distal segment ofthe distal tip can include a pull ring adjacent or immediately distalthereof. The distal tip can be configured for interacting between thepull ring and a distal face of catheter body.

In some examples, the proximal end of the distal segment of the distaltip can be external to the pull ring.

In some examples, the distal tip can be integral with the catheter body.The distal tip can include a proximal segment and a distal segmentextended from the proximal segment. The distal segment can besubstantially flexible and include a proximal end substantially alignedwith a pull ring internal thereto when configured in the funnel shape.

In some examples, the dilator can include a substantially tubularproximal segment and a distal segment distal of the proximal segment.The distal segment of the dilator can include a diameter greater thanthe proximal segment. The distal segment of the dilator can include acontact element extended radially outward from the distal segment andconfigured to contact and translate proximally the pull ring until beingaligned at or adjacent a distal end of the proximal segment of thedistal tip.

In some examples, the contact element can be an outward angled latch.

In some examples, the contact element can be an orthogonally outwardlatch.

In some examples, the contact element can be distal of the proximal endof the distal segment.

In some examples, a midpoint of the distal segment of the distal tip ina collapsed state transitions to being a distalmost petal tip of thefunnel shape in the deployed state distal of the catheter.

In some examples, a midpoint of the distal segment of the distal tip ina collapsed state transitions to being a distalmost flower-like petaltip of the funnel shape in the deployed state distal of the catheter.

In some examples, the dilator can include a proximal segment and adistal segment distal of the proximal segment. The distal segment caninclude a distal contact element extended radially outward from thedistal segment and configured to contact and translate proximally thepull ring until being aligned at or adjacent the proximal end of thedistal tip.

In some examples, the dilator can include a proximal contact elementtapering proximally from the distal contact element. The proximalcontact element can include a diameter less than the distal contactelement. In some examples, the distal contact element can be anoutwardly extend ring-like member. In some examples, the distal contactelement can include a semi-circle shape. In some examples, the distalcontact element can be connected to the pull ring.

In some examples, a midpoint of the distal segment in a collapsed statetransitions to being a distalmost petal tip of the funnel shape in thedeployed state distal of the catheter.

In some examples, a midpoint of the distal segment in a collapsed statetransitions to being a distalmost flower-like petal tip of the funnelshape in the deployed state distal of the catheter.

In some examples, the dilator can include a proximal segment and adistal segment distal of the proximal segment. The distal segment caninclude a greatest diameter greater than the proximal segment and caninclude a diameter larger than the proximal segment. A distal contactelement can include a transition from the distal segment to the proximalsegment and configured to contact and translate proximally the pull ringto cause an interference fit with the pull ring to transmit a force toexpand the distal tip to the funnel shape.

In some examples, the distal tip is configured to first expand to asubstantially conical shape before inverting to form the funnel shape.

In some examples, the proximal segment of the dilator is highly flexibleand includes a thin wall.

In some examples, the proximal segment of the dilator is highly flexibleand includes longitudinal string-like fibres to prevent it fromstretching under tension.

In some examples, upon forming the inverted funnel shape, aninterference force between the dilator and the pull ring is incapable ofmoving the pull ring proximally.

In some examples, the dilator tip can squeeze through the pull ring.

In some examples, the dilator tip is easily retracted through thecatheter.

In some examples, the dilator tip can include a proximal segment and adistal segment extended from the proximal segment. The distal segmentcan be substantially flexible and be at least partially positionedaround the proximal segment at least at a proximal end of the distalsegment. The distal tip can include a pull ring, which can include anexternal taper matching an internal taper of the proximal segment suchthat tapers lock together when forming the funnel shape.

In some examples, the braid extends circumferentially at a mid point ofthe distal tip to aid in defining a rounded inversion seam.

In some examples, the braid extends from proximal to distal end of thedistal tip thereby providing a rounded inversion seam.

In some examples, the braid includes a subset of filaments extended fromproximal to middle portions so that the filaments revert to extend backto the proximal portion forming a looped braid pattern, and theremaining filaments extend from a proximal end to a distal end such thata spiral portion is formed distal of the looped subset of filaments.

In some examples, the braid includes filaments extended from proximal todistal portions in a helical configuration.

In some examples, the braid includes an inversion hinge in or around themiddle portion.

In some examples, the proximal portion can be relatively stiff. Themiddle portion can be relatively flexible, and the distal portion caninclude a flexible helix.

In some examples, the distal tip can include a braid with proximal,middle and distal portions, wherein the distal portion includessufficient radial force to push the proximal portion radially outwardlywhile being configured to accommodate various vessel sizes in anatraumatic manner.

In some examples, a method of inverting an expansile catheter in a bloodvessel is disclosed. The method can include advancing the catheter to atarget site; and retracting, by a dilator at least partially within alumen of the catheter, a distal tip of the catheter, causing the distaltip to expand and invert to a funnel shape.

In some examples, the method can include restricting, by the funnelshape, flow in the blood vessel.

In some examples, the method can include withdrawing the dilator fromthe catheter; aspirating through the catheter to stimulate a thrombusinto a mouth of the funnel shape; and withdrawing the catheter with thecaptured thrombus from the patient.

In some examples, the method can include capturing the occlusivethrombus with a mechanical thrombectomy device; and withdrawing thethrombectomy device into the funnel shape of the catheter.

In some examples, the dilator may not be required. In such approaches,the collapsed tip can be corked onto the clot and aspiration suctionforce can pull the distal end proximally to invert the tip and createthe inverted funnel shape during aspiration.

Other aspects and features of the present disclosure will becomeapparent to those of ordinary skill in the art, upon reviewing thefollowing detailed description in conjunction with the accompanyingfigures.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further aspects of this disclosure are further discussedwith the following description of the accompanying drawings, in whichlike numerals indicate like structural elements and features in variousfigures. The drawings are not necessarily to scale, emphasis insteadbeing placed upon illustrating principles of the disclosure. The figuresdepict one or more implementations of the inventive devices, by way ofexample only, not by way of limitation. It is expected that those ofskill in the art can conceive of and combining elements from multiplefigures to better suit the needs of the user.

FIG. 1A depicts an expansile tip of an expansile catheter in a firstconfiguration with a dilator of this disclosure.

FIG. 1B depicts the expansile tip of the expansile catheter in anotherconfiguration with the dilator of FIG. 1A.

FIG. 1C depicts the expansile tip of the expansile catheter in anotherconfiguration with the dilator of FIG. 1A.

FIG. 2A depicts the expansile tip of an expansile catheter of FIGS.1A-1C, deployed to a target location, according to aspects of thepresent disclosure.

FIG. 2B depicts the expansile tip of an expansile catheter of FIGS.1A-1C, deployed to a target location, according to aspects of thepresent disclosure.

FIG. 2C depicts the expansile tip of an expansile catheter of FIGS.1A-1C, deployed to a target location, according to aspects of thepresent disclosure.

FIG. 2D depicts the expansile tip of an expansile catheter of FIGS.1A-1C, deployed to a target location, according to aspects of thepresent disclosure.

FIG. 3A depicts an expansile tip of an expansile catheter in a firstconfiguration with a dilator of this disclosure.

FIG. 3B depicts the expansile tip of the expansile catheter in anotherconfiguration with the dilator of FIG. 3A.

FIG. 4A depicts an expansile tip of an expansile catheter in a firstconfiguration with a dilator of this disclosure.

FIG. 4B depicts the expansile tip of the expansile catheter in anotherconfiguration with the dilator of FIG. 4A.

FIG. 5A depicts an expansile tip of an expansile catheter in thedeployed configuration with a dilator of this disclosure.

FIG. 5B depicts an expansile tip of an expansile catheter in thedeployed configuration with a dilator of this disclosure.

FIG. 5C depicts an expansile tip of an expansile catheter in thedeployed configuration with a dilator of this disclosure.

FIG. 6A depicts an expansile tip of an expansile catheter in thedeployed configuration with a dilator of this disclosure.

FIG. 6B depicts an expansile tip of an expansile catheter in thedeployed configuration with a dilator of this disclosure.

FIG. 6C depicts an expansile tip of an expansile catheter in thedeployed configuration with a dilator of this disclosure.

FIG. 7A depicts the expansile tip of an expansile catheter of FIG. 6B,being deployed according to aspects of the present disclosure.

FIG. 7B depicts the expansile tip of an expansile catheter of FIG. 6B,being deployed according to aspects of the present disclosure.

FIG. 7C depicts the expansile tip of an expansile catheter of FIG. 6B,being deployed according to aspects of the present disclosure.

FIG. 8A depicts the expansile tip of an expansile catheter beingdeployed according to aspects of the present disclosure.

FIG. 8B depicts the expansile tip of an expansile catheter of FIG. 8A,being deployed according to aspects of the present disclosure.

FIG. 8C depicts the expansile tip of an expansile catheter of FIGS.8A-8B, being deployed according to aspects of the present disclosure.

FIG. 9A depicts an expansile tip of an expansile catheter in thedeployed configuration with a dilator of this disclosure.

FIG. 9B depicts the expansile tip in the deployed configuration of FIG.9A with the dilator removed.

FIG. 10A depicts an expansile tip of an expansile catheter in a firstconfiguration, according to aspects of the present disclosure.

FIG. 10B is a close-up of the expansile tip of FIG. 10A in the deployedconfiguration, according to aspects of the present disclosure.

FIG. 11A depicts an expansile tip of an expansile catheter in a firstconfiguration with a dilator of this disclosure.

FIG. 11B depicts the expansile tip of the expansile catheter in anotherconfiguration with the dilator of FIG. 11A.

FIG. 12A depicts a side view of an expansile tip of an expansilecatheter in one configuration according to this disclosure.

FIG. 12B depicts a rear view of the expansile tip of FIG. 12A in anotherconfiguration according to this disclosure.

FIG. 12C depicts a side view of the expansile tip of FIG. 12B accordingto this disclosure.

FIG. 12D depicts a front view of the expansile tip of FIG. 12B accordingto this disclosure.

FIG. 13 depicts a side view of an expansile tip of an expansile catheterin one configuration according to this disclosure.

FIG. 14A depicts a side view of an expansile tip of an expansilecatheter in one configuration according to this disclosure.

FIG. 14B depicts a rear view of the expansile tip of FIG. 14A in anotherconfiguration according to this disclosure.

FIG. 14C depicts a side view of the expansile tip of FIG. 14B accordingto this disclosure.

FIG. 14D depicts a front view of the expansile tip of FIG. 14B accordingto this disclosure.

FIG. 15A depicts a side view of an expansile tip of an expansilecatheter in one configuration according to this disclosure.

FIG. 15B depicts a close-up view of the expansile tip of FIG. 15Aaccording to this disclosure.

FIG. 15C depicts a close-up view of the expansile tip of FIG. 15Aaccording to this disclosure.

FIG. 16A depicts a close-up view of the expansile tip of FIG. 15Aaccording to this disclosure.

FIG. 16B depicts a close-up view of the expansile tip of FIG. 15Aaccording to this disclosure.

FIG. 16C depicts a close-up view of the expansile tip of FIG. 15Aaccording to this disclosure.

FIG. 16D depicts a close-up view of the expansile tip of FIG. 15Aaccording to this disclosure.

FIG. 16E depicts a close-up view of the expansile tip of FIG. 15Aaccording to this disclosure.

FIG. 16F depicts a close-up view of the expansile tip of FIG. 15Aaccording to this disclosure.

FIG. 17 is a flow diagram outlining a method of use for the systemaccording to aspects of the present disclosure.

DETAILED DESCRIPTION

The objective of the solution of this disclosure is an invertible,expansile catheter capable of providing both local flowrestriction/arrest with a large distal facing mouth and a tailored,highly flexible body section capable of navigating tortuous areas of thevasculature to reach an occlusive clot. Flow restriction and largetipped designs offer substantially greater aspiration efficiency. Suchadvantages can also be especially beneficial in the case of strokeintervention procedures, where vessels in the neurovascular bed areparticularly small and circuitous, and as a result a tailored axial andbending stiffness profile can inhibit kinking and binding. The cathetercan also be compatible with relatively low-profile access sheaths andouter catheters, so that a puncture wound in the patient's groin (in thecase of femoral access) can be easily and reliably closed. The cathetercan also feature internal and/or external low-friction liners, and anouter polymer jacket or membrane disposed around the support structure.

These improvements can lead to safe and more rapid access of a catheterand other devices to complex areas in order to remove occlusions andshorten procedure times. While the description is in many cases in thecontext of mechanical thrombectomy treatments, the systems and methodsmay be adapted for other procedures and in other body passageways aswell.

Accessing the various vessels within the vascular system, whether theyare coronary, pulmonary, or cerebral, involves well-known proceduralsteps and the use of a number of conventional, commercially-availableaccessory products. These products, such as angiographic materials,rotating hemostasis valves, and guidewires are widely used in laboratoryand medical procedures. When these products are employed in conjunctionwith the system and methods of this disclosure in the description below,their function and exact constitution are not described in detail.

Referring to the figures, in FIGS. 1A-1C there is illustrated a cathetersystem 100 for removing an occlusive clot C (shown in FIGS. 2A-2D) froma vessel BV of a patient. System 100 can be an aspiration catheter oftraditional construction or can have rapid-exchange (RX) type features,many of which can greatly increase the speed and efficiency of the clotretrieval procedure. In particular, FIGS. 2A-2D illustrate catheter body50 of catheter 100 deployed to a target blood vessel BV, according toaspects of the present disclosure. System 100 can be actuatable to adeployed state, which is shown in FIG. 1C. A dilator 70 can bepositioned at least partially within the lumen 47 of the catheter body50. A distal end 78 of the dilator 70 can be connected to a distal tip51 of the catheter body 50. The dilator 70 can be retractable to invertthe distal tip 51 and form a funnel shape in the deployed state, asshown with system moving proximally one or more distances D from aninitial elongate state of FIG. 1A to deployed in FIG. 1C. While FIG. 1Cdoes show the deployed state, dilator 70 would be fully removed prior toaspiration in order to maximize the flowrate possible through thecatheter body of tip 51 and also to allow passage of a microcatheter andstentriever. Dilator 70 may also include a distally protrudingmicrocatheter portion such that a stentriever could be uncovered acrossthe clot during activation of the funnel and removal of the dilator 70.

For an OD of approximately 2 mm catheter body in an M1, the ratio ofcollapsed OD to deployed funnel OD is contemplated to range betweenapproximately 2.5 mm to 4.0 mm. At the carotid T, the ratio iscontemplated to range 4.0 mm to 6.0 mm. Where the ratio is contemplatedto range 5.0 to 8.0 mm, the ratio is feasible for ICA vessel placement.Where the ratio is contemplated to range 2.5 to 5.0 mm, the ratio isenvisaged to target M1 and Carotid T locations.

In some examples, a ratio between the collapsed OD to funnel OD isdependent on the length of the corresponding catheter tip whencollapsed. Preferably, the tip collapsed length can be range between 3mm and 8 mm (e.g., the distances D in the figures) for expanded ODs ofapproximately 2.5 mm to 5.0 mm. Yet, in some examples, the ratio can bea function of the diameter the braid is set at and the braid angle.

System 100 can be configured to expand to a wide range of target vesseldiameters, such as a carotid terminus (3.2-5.2 mm), a horizontal M1segment of the Middle Cerebral Arteries (1.6-3.5 mm), and/or theInternal Carotid Artery (ICA, 2.7-7.5 mm). If the catheter system 100 isthen retracted from an M1 segment to the ICA (or another route with aproximally increasing vessel inner diameter), the radial force of thetip 50 once in the funnel shape can continue to seal with the vesselacross a range of vessel sizes. Further, a tip 50 capable of a range oftarget vessel diameters can also seal at vessel bifurcations which canhave a wider cross-sectional area than the vessel proximal and vesselsdistal to the bifurcation. Preferably, the tip 51 is inverted to thedeployed funnel shape at the treatment location to avoid having toadvance a funnel-shaped catheter tip through the vasculature.

The ideal nominal diameter of the catheter system 100 depends on thelocation of the target clot and/or a diameter of any other catheterthrough which catheter system 100 is to be delivered. For retrieval ofclots in the intracranial vessels of the cerebral vascular bed, wherevessel diameters at the M1 locations are commonly around 3 mm, anapplicable system can have an outer catheter with an inner diameter of0.065″ to 0.080″ and an RX clot retrieval catheter with an innerdiameter of 0.055″-0.070″. Upon deployment, the maximum diameter of thetip 50 can be a minimum of 2.5 mm (but in some instances up to 8 mm),allowing it to seal against the walls of the vessel and providing afunnel-shape distal mouth as large as the vessel itself. In someinstances, the tip 51 can also provide an opening large enough to opposebifurcations and/or proximal vessel locations. This seal, in combinationwith a maximized proximal lumen of the disclosed RX system over aconventional catheter, offers benefits in terms of aspiration force atthe face of the clot and increased flowrates with a design that utilizesthe larger inner diameter of the outer catheter.

In some examples, distal tip 51 can include a proximal segment 55 and adistal segment 52 extended from the proximal segment 55. Segment 52 canbe substantially flexible and a proximal end 53 of the distal segment 52can be extended from the proximal segment 55 and include a pull ring 54adjacent and/or connected to a distal end 58 of the distal segment 52.Pull ring 54 in this example can be positioned on a proximal face 54 ofthe distal end inside the distal segment 52. In this respect, segment 52can be an expandable sheath attached under pull ring 54.

A midpoint of the distal segment 52 in the collapsed state, as in FIG.1A, can transition to being a distalmost atraumatic end of the funnelshape in the deployed state, as in FIG. 1C, distal of the catheter body50, as dilator 70 moves proximally a distance D while connected todistal end 58. Distal segment 52 in a collapsed state can besubstantially tubular (FIG. 1A) whereas in in the deployed state afterproximally moving distances D (FIG. 1B, FIG. 1C) segment 52 can includethe funnel shape.

In some examples, the funnel shape formed by the inverted distal segment52 can include an air cushion 60 formed between the distal end 58 andthe pull ring 54. In some examples of the funnel shape, ring 54 can bepositioned inside the lumen 47 to form a compression lock therewiththereby securing segment 52 in its expanded, funnel shape. Thecompression lock can be defined as the interference fit by fitting thering 54 within lumen 47 whose inner diameter may be slightly less thanthe outer diameter of ring 54.

In some examples, the distal segment 52 can be divided into a proximalbraid portion and a distal spiral braid portion. An elastomeric membranecan be interlaced, coated thereon, or extend over the braid or invertingframe structure. For example, an elastic membrane can follow thecontours of the underlying braided strut framework of tip 51. Theelastic membrane can at least partially run the length of tip 51. Inother examples, tip 51 can be further coated with a lubricious materialsuch as commercially available hydrophilic coatings (e.g., Surmodics,Harland, Biocoat, Covalon) or may include low friction materials orfillers. The membrane can also float over the inverting supportstructure such that the inverting structure struts can move freely underthe membrane. In some examples, the membrane incapsulates the invertingsupport structure.

In some examples, dilator 70 can include a proximal segment 76 and adistal segment 77 distally extended thereof. Segment 77 can include adiameter greater than the proximal segment 76 and include a contactelement 71 extended radially outward to contact and translate proximallythe pull ring 54 one or more distances D until being aligned at oradjacent the proximal end 53 of the distal segment 52. In this example,contact element 71 can be a sudden, angled outward transition thatcreates a contact surface that forms an interference fit with distal end58 of segment 52.

In some examples, dilator 70 can be solid and/or hollow with a lumentherein. Dilator 70 can include an inner lumen 75 be substantiallyelongate (e.g. tubular) at its proximal segment 76 and taper radially,outwardly to distal segment 77 with distal end 78 having a largerdiameter than the proximal segment 76. This taper can commence at atransition or junction 73 between segments 76, 77. Dilator 70 can behighly flexible proximal to tip 51. Dilator 70 can include one or morefibers as part of its structure that are configured for reinforcement tonegate elongation thereof. In some examples, segment 76 can be highlyflexible or substantially more flexible than the distal segment 77. Thedistal segment 77 in some examples can still have adequate flexibilityto contort around tortuous vasculature. Any stiff portions required totransmit force to ring 54 can be kept as short as possible to maintainlateral flexibility of the tip 51.

In one example, system 100 can use an aspiration source to capture aclot, as shown in FIGS. 2A-2D. In particular, FIGS. 2A-2D show system100 being deployed and then aspirating clot C, preferably with dilator70 fully removed as in FIG. 2D. The main advantage of using dilator 70as shown and described is that it can be removed after inversion of thetip such that the full cross-sectional area of catheter 50 can be usedto maximize flow rate and force on the clot C through catheter body 50when in the funnel shape, as shown. As also shown in FIGS. 2A-2D, thefunnel shape formed by tip 51 being expanded can seal with the walls ofthe blood vessel BV or the seal or seals can be selectively activated(e.g., by moving dilator 70 proximally or distally).

Tip 51 once expanded can include a large, atraumatic mouth for efficientaspiration. Tip 51 can include kink-resistant characteristics to aid inadvancing it to the target location. It can therefore have multipleconfigurations, or be fabricated from multiple materials, as discussedherein, so as to maintain lateral flexibility but avoid expanding orkinking in compression. The large distal mouth of tip 51 shown in FIGS.2A-2D can offer improved performance over conventional fixed-mouthdesigns, which can be hindered by having firm, fibrin-rich clots lodgein the tip and/or by having softer portions of the clot shear away. Itis less likely for clots to become lodged in the tubular section of thedisclosed invertible, expansile tip 51 due to the progressivecompression of the clot upon entry to the reducing funnel shape.

Struts of the tip 51 can be formed from Nitinol or another shape-memorymaterial with sufficient elastic strain capacity such that the elasticlimit would not be exceeded when the tip is constrained and delivered inthe collapsed configuration within an outer catheter or during expansionto invert to a funnel shape. The struts can be heat set expanded only topromote inversion at a predetermined location, said expanded area beingrestrained by an outer membrane covering. Actively inverting in thisrespect the frame then pushes the membrane outwardly by increasing theradial force of the frame. In another case, the framework can beconstructed from wire, allowing a non-superelastic material like astainless-steel alloy to be employed, since the wires would be free tomove independent of one another. It is appreciated that a framework oftip 51 constructed of wire using superelastic or shape memory materialscan also be envisaged, such a device offering improved torque anddurability characteristics. In another case, a framework of tip 51 canbe laser cut or formed with wire from a non-superelastic or shape memorymaterial that accommodates strain by including cells or bends, with alower degree of strain required to move from a collapsed state fordelivery to an expanded state for clot retrieval. For example, theframework can include additional cells, longer cell struts, and/or lowercell angles to reduce strain requirements.

FIGS. 3A-3B depicts another invertible, expansile tip 251 going from afirst configuration, shown in FIG. 3A, with dilator 270 and then aclose-up of the funnel-shape, deployed configuration of tip 251 in FIG.3B without dilator 270. While not shown, dilator 270 could be includedin FIG. 3B as needed or required. It is understood that similarreference numbers examples discussed throughout this disclosure indicateidentical or functionality similar elements. With that, dilator 270 caninclude inner lumen 275 with proximal segment 276 and distal segment 277terminating in distal end 278 distal of the proximal segment 276.Dilator 270 can include distal contact element 271 extended radiallyoutward from the distal segment 277. Element 271 can be configured tocontact and translate the pull ring 254 until being aligned at oradjacent the proximal end 258 of the distal segment 252. Dilator 270 mayalso include a sudden, angled outward transition (e.g., element 271 herebeing substantially orthogonal to the outer surface of dilator 270) toform a contact surface that forms an interference fit with distal end258 of segment 252. Dilator 270 can also have a proximal contact element273 proximally spaced from the distal contact element 271 and similarlyextended radially outward from the distal segment 277. In some examples,a groove can be defined between elements 271, 273 in which the pull ring254 can be positioned or otherwise connected. In this respect, opposedfaces of the space or groove between elements 271, 213 can be planar orotherwise conform to the shape of ring 254. In some examples, element271 can urge or otherwise couple to end 258 while element 273 can urgeor otherwise couple to ring 254. In some examples, element 273 caninclude a diameter less than element 271, or vice versa. From element271 to distal end 278, dilator 270 can taper to a smaller diameter.

As in system 100, an interference fit can be provided in catheter body250 between distal end 258 of the distal tip 251 when in the funnelshape of the deployed state. In some examples, at least one of thecontact elements 271, 273 can include a magnetic connector operable tomagnetically retract the distal tip 251 to the funnel shape of thedeployed state. In so doing, the magnetic coupling therein canfacilitate the actuation of tip 271 into the inverted, funnel-shape ofthe deployed state. Segment 276 and/or the segment 277 can include asubstantially thinned wall. Preferably, going from segment 276 tosegment 277, dilator can include a relatively thin wall proximal to tipfor optimum flexibility.

Segment 276 in some examples can include string-like filamentsconfigured to prevent elongation under tension. With respect to tip 251,its proximal segment 255 can be stiffer than the distal segment 252.However, this example is not so limited and instead segment 252 can bestiffer than the proximal segment 255. In some examples, segment 252 caninclude a resistance or bias to remain in its substantially tubularshape prior to deployment, as in FIG. 3A. Proximal segment 255 and/ordistal segment 252 can also include a braided structure, similar tosegments 152, 155. For examples, segments 252, 255 can be constructedfrom a framework of struts that include a memory alloy. Similar tosegment 52, segment 252 can be divided into a proximal braid portion anda distal spiral braid portion as well include one or more elastomericcoating(s) or membrane(s). The braid and spiral portions of this examplecan be created, for example, by finishing the ends of the clockwisebraid wires at a midpoint between the ends of the counterclockwise braidwires such that the counterclockwise braid wires form a spiral past thispoint. In some examples, this can be achieved by cutting the clockwisewires of a standard braid on a circumferential plane at a locationbetween the ends of the braid. In another example, clockwise braids canbe looped to extend proximally such that a denser proximal braid ispaired with a distal spiral portion.

FIGS. 4A-4B depicts another invertible, expansile tip 351 of catheter350 going from a first configuration, shown in FIG. 4A, with dilator 370and then a close-up of the funnel-shape, deployed configuration in FIG.4B, after dilator 370 has been retracted to invert tip 351 to thefunnel-shape. In this instance, proximal segment 355 of tip 351 caninclude a distal end 353 that can include a magnetic element capable ofcoupling with corresponding ring 354, which in turn can be magnetized.Ring 354 as shown can be configured to magnetically couple with end 353so tip 351 can maintain the inverted, funnel shape shown in FIG. 4B. Insome examples, ring 354 and/or end 353 can be made from a ferrous metalsuch that one is attracted to the other. Alternatively, both featuresare magnetic such that the south pole of one engages with the north poleof the other to form a stronger engagement than if a ferrous metal wasused. In yet another embodiment, dilator 370 can include magneticfeatures to engage with the pull ring 354 to provide sufficient force toinvert tip 351 to its inverted, funnel-shape.

In some examples, dilator 370 can include inner lumen 575, distalsegment 377 terminating in distal end 278 distal of the proximal segment376, with each including similar diameters. Contact element 371 ofdilator 370 can be a distal end of a notch or gutter or groove or recessof dilator whereas contact element 372 can be the proximal end of thesame notch or gutter or groove or recess. In some examples, element 371can be magnetic so as to grip ring 354 (e.g., by constructing ring 354out of one or more ferrous materials), and pull ring 354 proximallyduring retraction of the dilator 370. Ring 354, which can be coupled toend 358, can be positioned therebetween respective to said notch orgutter or groove or recess and/or therearound. As arranged, distalsegment 377 translate pull ring 354 until being aligned at or adjacentthe proximal end 358 of the distal segment 352 thereby inverting segment352 to form the atraumatic funnel-shape of FIG. 4B. In some examples,the proximal end 353 of the distal tip 351 and the pull ring 354 can belocked together in the deployed state by the corresponding magneticcoupling therebetween. The proximal end 353 of the distal tip 351 andthe pull ring 354 can each include planar mating surfaces or matingsurfaces profiled with ridges and/or interlocking recesses. For example,mating surfaces can be tapered for an interlocking taper lockinteraction. In other examples, mating surfaces can be configured tosnap lock together.

FIG. 5A depicts another invertible, expansile tip 451 of catheter 450with dilator 470. Tip 451 can include proximal segment 455 and distalsegment 452 extended from the proximal segment 455 and beingsubstantially flexible. A proximal end 453 of the distal segment 452 canbe positioned on an outer surface of the distal tip 451. Similar topreviously described tips, a pull ring 454 can be adjacent orimmediately distal of segment 455 so ring 454 can be used to pull andcause segment 452 to invert to the funnel-shape of FIG. 5A. In someexample, proximal end 453 of the distal segment 452 can be external tothe pull ring 454. Aligning ring 454 in this respect and attachingproximal end 453 as shown to the OD of catheter 450 and positionmembrane structure attached to distal face of pull ring. In turn, thisattachment allows membrane to smoothly taper distally when inverted.

FIG. 5B depicts another invertible, expansile tip 551 of catheter 550with dilator 570 of this disclosure. Distal tip 551 as shown can beintegral with the catheter body 550, including segment 555 beingintegral with segment 552. Dilator 570 of this example can also includea greatest diameter at or around contact element 573, which here can bean outward bulge or ring-like extrusion configured to be arrangedinternal to ring 554 and form an interference fit with element thatdistally tapers from element 573. As shown, ring 554 fits under catheterbody 550, the proximal face of membrane structure is in line with orintegral with distal face of catheter body 550, and the membranestructure is attached under pull ring 554. In turn, this attachmentallows membrane to smoothly taper distally when inverted.

FIG. 5C depicts another invertible, expansile tip 651 of catheter 650 inthe deployed configuration with dilator 670. As shown, dilator 670 caninclude a distal segment 677 distal of the proximal segment 676 with adiameter greater than the proximal segment 676. The change in diametercan be gradual to form an elliptical or otherwise curved shape. Distalsegment 677 can include a contact element 671 extended radially outwardfrom the distal segment 677 and configured to contact and translateproximally the pull ring 654 until being aligned at or adjacent a distalend of the proximal segment 655. Element 671 as can be seen can be anoutward angled latch. For example, element 671 as shown can include beangled distally so as to form an acute angle between it and the outersurface of dilator 670. This latch in turn can prevent the distal end ofsegment 652 from disengaging therefrom in the funnel-shape, as shown.

FIG. 5C depicts another invertible, expansile tip 651 of catheter 650 inthe deployed configuration with dilator 670. As shown, dilator 670 caninclude inner lumen 675, a distal segment 677 with distal end 678 distalof the proximal segment 676 with a diameter greater than the proximalsegment 676. The change in diameter can be gradual to form an ellipticalor otherwise curved shape. Distal segment 677 can include a contactelement 671 extended radially outward from the distal segment 677 andconfigured to contact and translate proximally the pull ring 654 untilbeing aligned at or adjacent a distal end of the proximal segment 655.Element 671 as can be seen can be an outward angled latch. For example,element 671 as shown can include be angled distally so as to form anacute angle between it and the outer surface of dilator 670. This latchin turn can prevent the distal end of segment 652 from disengagingtherefrom in the funnel-shape, as shown.

FIG. 5C depicts another invertible, expansile tip 651 of catheter 650 inthe deployed configuration with dilator 670. As shown, dilator 670 caninclude inner lumen 675, a distal segment 677 with distal end 678 distalof the proximal segment 676 with a diameter greater than the proximalsegment 676. The change in diameter can be gradual to form an ellipticalor otherwise curved shape. Distal segment 677 can include a contactelement 671 extended radially outward from the distal segment 677 andconfigured to contact and translate proximally the pull ring 654 untilbeing aligned at or adjacent a distal end of the proximal segment 655.Element 671 as can be seen can be an outward angled latch. For example,element 671 as shown can include be angled distally so as to form anacute angle between it and the outer surface of dilator 670. This latchin turn can prevent the distal end of segment 652 from disengagingtherefrom in the funnel-shape, as shown.

Element 671 is not so limited, however, and can instead by substantiallyorthogonal with respect to the outer surface of dilator 670. Element 671may also be distal of the proximal end 653 of segment 652, whereby end653 can be positioned on an outer surface of segment 655. In someexamples, a midpoint of the distal segment 652 in a collapsed statetransitions to being a distalmost petal tip of the funnel shape in thedeployed state distal of the catheter 650. System 600 in this respectcan include one continuous petal or a plurality of radially separateddistalmost flower-like petal tips that form the funnel shape. In otherexamples, the funnel-shape of system 600 can be more pointed, or lessatraumatic than the rounded funnel-shapes of FIGS. 5A-5B.

FIG. 6A depicts another invertible, expansile tip 751 of catheter 750 inthe deployed configuration with a dilator 770 of this disclosure. Asshown, contact element 771 of dilator 770 is distal of and attached totip 751 and provides a relatively smooth transition for clot captureand/or use of a stentriever therein. By arranging dilator 770 as shownwith respect to tip 751, the inner diameter of system 700 being reducedon account of distal end 758 of segment 752 being positioned at leastpartially inside the inner diameter of system 700. Advantageously, theproximal face of pull ring 754 abuts the distal face of the catheterbody 750 and the membrane/framework can be attached under the pull ring754. In this example, the proximal membrane structure is attached to theOD of catheter 750 which allows the membrane to smoothly taper distallywhen inverted.

FIG. 6B depicts another invertible, expansile tip 851 of catheter 850 inthe deployed configuration with a dilator 870 of this disclosure. Asshown, contact element 871 of dilator 870 is distal of and attached totip 851. Here, since end 858 of segment 852 is coaxial with segment 855in the deployed, funnel-shape, the inner diameter between segments 855,852 is substantially similar, if not equivalent. As shown, tip 851 canalso include a relatively sharper edge in the funnel-shape, as comparedto tip 751. Here, advantageously the proximal face of ring 854 abuts thedistal face of the catheter body 850 and the membrane/framework isattached to the distal face of ring 854. Moreover, this causes a sharperinversion of funnel and the proximal membrane structure attached to anOD of catheter 750.

FIG. 6C depicts another invertible, expansile tip 951 of catheter 950 inthe deployed configuration with a dilator 970 of this disclosure. Asshown, contact element 971 of dilator 970 is distal of and attached totip 951. In particular, distal contact element 971 extended radiallyoutward from the distal segment 977 and configured to contact andtranslate proximally the pull ring 954 until being aligned at oradjacent the proximal end 953 of the distal tip 951. A proximal end faceof element 971 can be arranged to contact ring 954, which can be on adistal face of distal end 958 of segment 952. Here the proximal face ofring 954 abuts the distal face of the catheter body 950 and themembrane/framework is attached to the distal face of ring 954 and arelatively sharper inversion of funnel results.

As shown, end 958 can have a biased curve that facilitates contactbetween ring 954 and end 958. In the funnel-shape configuration shown,the curve can extend proximally before returning distally to urge ring954 to couple with the proximal face of element 971. In some examples,element 971 can include or be an outwardly extend ring-like member.Element 971 can also include a semi-circle shape.

FIGS. 7A-7C illustrates tip 851 but with a modified, sharperfunnel-shape, previously described in FIG. 6B, transitioning from thecollapsed, tubular state of FIG. 7A to the deployed, funnel-shape ofFIG. 7C. In particular, dilator 870 is seen coupled to ring 854 at itsrespective contact element. FIG. 7B shows dilator 870 having beenretracted a first distance causing segment 852 to initiate its expansionas its midsection begins inverting. FIG. 7C shows ring 854 having beenproximally translated by dilator 870 until contacting the distal face ofsegment 855. In turn, segment 852 is completely inverted to thefunnel-shape. Here, ring 854 has a similar diameter to segment 855 suchthat an abutment is formed between the ring 854 and segment 855 in theexpanded state. Advantageously, this minimal difference in inner andouter diameters between the proximal and distal ends of catheter 850optimizes its relatively low outer profile and large inner diameter.

FIGS. 8A-8C illustrates another expansile, invertible tip 1051 ofcatheter 1050 of this disclosure being deployed by being inverted inconnection with dilator 1070, according to aspects of the presentdisclosure. In particular, tip 1051 is shown transitioning from thecollapsed, tubular state of FIG. 8A to the deployed, funnel-shape ofFIG. 8C. A proximal face of element 1071 is coupled to ring 1054. FIG.8B shows dilator 1070 having been retracted a first distance causingsegment 1052 to initiate its expansion as its midsection beginsinverting. In the state of FIG. 8B, segment 1052 can include a generallyconical shape before inverting. FIG. 8C shows ring 1054 having beenproximally translated by dilator 1070 until be arranged proximate thedistal face of segment 1055 (e.g., here, internal to segment 1055). Inturn, segment 1052 is completely inverted to the funnel-shape shown inFIG. 8C. Ring 1054 can have a diameter to less than an inner diameter ofsegment 1055 such that an abutment is formed between the ring 1054 andthe inner surface of segment 1055 in the expanded state.

In some examples, segment 1077 of dilator 1070 can be ultra soft toprovide sufficient interference with pull ring 1054 to transmit a radialforce sufficient to cause segment 1052 to expand and invert, as shownbetween FIGS. 8A-8C. In some examples, segment 1076 can be highlyflexible so that it does not contribute significantly to stiffness ofsystem. To achieve this, segment 1076 can include a relatively thin walland may include longitudinal string-like fibers to prevent it fromstretching under tension.

In some examples, once the inverted funnel shape shown in FIG. 8C hasbeen formed, the interference force between the dilator 1070 and ring1054 can be insufficient to move ring 1054 more proximally and the tipof dilator 1070 (e.g., segment 1077) squeezes through ring 1054. Assegment 1077 is sized to have a small clearance with the lumen ofsegment 1055, segment 1077 can be easily retracted through the cathetersystem 1000. In some examples, dilator 1070 can be re-advanced to pushring 1054 distally and un-invert the funnel-shape to a collapsed,tubular sheath of FIG. 8A. In some examples, though not shown, a secondstiffer dilator may be supplied for the purpose of collapsing tip 1051,once inverted and expanded within a blood vessel, where the firstdilator 1070 may be present.

FIGS. 9A-9B illustrate another expansile, invertible tip 1151 ofcatheter 1150. In particular, FIG. 9A shows tip 1151 with dilator 1170in the expanded, funnel-shape configuration. FIG. 9B shows tip 1151 inthe same configuration but with dilator 1170 having been retracted andremoved from tip 1151. Here, the distal face of element 1171 is coupledto the proximal face of end 1158 so that tip 1151 is compressed throughring 1154. In turn, an inner diameter of end 1158 is coupled to ring1154. In this example, coupling end 1158 to ring 1154 as described andshown allows tip 1151 to form a gradual smooth curve for entry ofaspirated clot and or stent retriever devices. Moreover, ring 1154 beingsized smaller than main catheter body inner diameter of segment 1155allows for the pull ring 1054 to wedge or lock in position as segment1177 of dilator 1170 compresses through it.

FIGS. 10A-10B illustrates tip 1251, according to aspects of the presentdisclosure, whereby FIG. 10A shows the tip 1251 when extended in thetubular configuration and FIG. 10B is a close-up of tip 1251 ring 1254has been retracted to cause segment 1252 to expand and invert to thefunnel shape. Ring 1254 can include an external taper that matches aninternal taper 1259 positioned at a distal end of segment 1255. As shownmore clearly in in FIG. 10B which shows the closed up of the coupledtapers, the corresponding tapers can couple and/or lock together. Whileonly tapered surfaces are shown in FIGS. 10A-10B, it is contemplatedthat other interlocking surfaces can be used as needed or required.

FIGS. 11A-11B depicts another expansile tip 1351 of catheter 1350 goingfrom a first, tubular configuration in FIG. 11A with dilator 1370 andthen to the expanded, inverted funnel-shape, deployed configuration ofFIG. 11B. Dilator 1370 can include a contact element 1371 that includesthe greatest diameter of dilator 1370 and then progressively, distallytapers therefrom for gradual radial compression of clot. Here, ring 1354can include a similar diameter to the diameter of segment 1355 such thatan abutment therebetween can prevent ring 1354 from moving proximallyinto the lumen of segment 1355, as shown in FIG. 11B. Distal end 1358 ofsegment 1352 is attached within an inner diameter of ring 1354, whichprovides the interference fit between end 1358 and/or ring 1354 withelement 1371 of dilator 1370. Advantageously, in this example there isless of a difference in inner diameter between segment 1355 and ring1354 such that clots can be less restricted from entering the lumen ofsegment 1355.

Further, by folding segment 1352, as shown, to extend distally from theinner diameter of ring 1354 and reverting to extend proximally over theouter diameter of ring 1354, segment 1353 can expand and invert to forma rounded feature for atraumatic funnel configured to interact and sealwith a vessel wall.

If tip 1351 were manufactured to be stiff, it would form too large around profile and have the potential of kinking when collapsed fordelivery through an outer balloon guide or long guide sheath. Kinkingcan also prevent tip 1351 from forming a gradual taper in the deployed,funnel-shape configuration and may form a snag point for stentrieversduring retraction in the catheter lumen. Therefore, configuring tip 1351with a flexible portion can allow it to first form a soft compressiblerounded feature in the collapsed configuration that will recover to forma progressive taper extending distally form the inner diameter of ring1354 to aid in compression of clot during aspiration and to provide anunhindered path for collapsing a stentriever during retraction into thecatheter lumen.

FIG. 12A depicts an example construction of one expansile, invertibletip 1451, which can include a braid with proximal 1447, middle 1445, anddistal 1443 segments. Middle segment 1445 can include filaments thatextend from proximal to a transition point with distal segment 1443,then they revert to extend back proximally forming a braid pattern.Distal segment 1443 can include filaments that extend from proximal todistal in a helical configuration and/or can include sufficient radialforce to push proximal segment 1447 radially outwardly while beingconformable to accommodate various vessel sizes in an atraumatic manner.A helical pattern can allow for a wider range of vessel size range thana braid as the helical wires will create a spiral pattern that canadjust more easily than a braid pattern. Distal segment 1443 can extendcircumferentially at or around the transition between segments 1445,1443 to aid in defining a less rounded inversion seam at the vesselwall.

FIGS. 12B-12D depicts views of tip 1451 once expanded and inverted tothe funnel shape, according to this disclosure. In particular, FIG. 12Cis a side plane view of tip 1451 with an example coating (though acoating is not necessarily required) whereas FIG. 12D is a front planview of segment 1451 and FIG. 12B is a rear plan view of segment 1451.As shown in FIG. 12D, segment 1443 and its helical configuration canconvert segment 1443 to spiral during inversion. As is also evident inFIG. 12C, along the lower dashed lines depicts the inversion seam of asharper inversion seam design in comparison to a rounded inversion seamthat can interact with the vessel wall during use. FIG. 12B showssegments 1447 and 1445 which form the braid's integrity and provide aninversion hinge at the transition point between segments 1445, 1443.Though not shown, it is contemplated that a coating or membrane asdescribed in this disclosure could be used with tip 1451 as needed orrequired.

FIG. 13 depicts an example construction of one expansile, invertible tip1551, which can include a braid with proximal 1547, middle 1545, anddistal 1543 segments, whereby the braid of tip 1551 may extend fromproximal to distal end. Tip 1551 can provide a more rounded inversionseam that can interact with the vessel wall during use.

FIG. 14A depicts an example construction of one expansile, invertibletip 1651, which can include a braid with proximal 1647, middle 1645, anddistal 1643 segments. Segment 1639 is proximal of segment 1647 andportion 1641 represents a transition between each segment. Segment 1647can be relatively stiff, segment 1645 can be relatively flexible, andsegment 1643 can include a helical configuration with respect to itsfilaments. Middle segment 1645 can in turn be configured to distributethe radial force over a larger region during the inversion step of tip1651. Middle segment 1645 being relatively flexible at the mid-sectioncan also lower structure inflection forces during inversion especiallywith the added constraints of a low profile vessel, thus reducing radialforce exerted by the structure and potential vessel trauma.

FIGS. 14B-14D depicts views of tip 1651 once expanded and inverted tothe funnel shape, according to this disclosure. In particular, FIG. 14Cis a side plane view of tip 1651 whereas FIG. 14D is a front plan viewof segment 1651 and FIG. 14B is a rear plan view of segment 1651. Asshown in FIG. 14D, segment 1543 and its helical configuration canconvert segment 1543 to spiral during inversion. As is also evident inFIG. 14C, the inversion seam of the rounded lower corners segment 1645can interact with the vessel wall during use. FIG. 14B shows segments1647 and 1645 which form the braid's integrity and provide an inversionhinge at the transition point between segments 1645, 1643. An inversionhinge can be applied by heat setting the filaments to have a largerdiameter at the center than the proximal and distal ends to promoteinflection, the membrane having sufficient resistance to expansion tohold the enlarged diameter in a substantially tubular shape in line withproximal and distal segments in the collapsed configuration. This can bedone with a non-shape memory material by using an oversized braid andreducing the distal and proximal diameters through attachment means tothe distal pull ring and proximal catheter body respectively (e.g.,reflowing jacket material, adhesive or by a restraining ring). Thoughnot shown, it is contemplated that a coating or membrane as described inthis disclosure could be used with tip 1651 as needed or required.

FIGS. 15A-16F depicts views of an expansile, invertible tip 1751according to this disclosure. In FIG. 15A, tip 1751 can include abraided construction with segments 1755 and 1752. Segment 1752 caninclude a proximal portion 1751 and a distal portion 1759, each with abraid pattern (e.g., the same pattern or a different pattern). Atransition portion 1753 can be positioned between segments 1755 and1752. In some examples of tip 1751, braid wires can loop around ring1754 to allow rotation of the braid about ring 1754 during inversion,which can facilitate complete inversion of the distal segment 1752. FIG.15A is denoted strictly for illustrative purposes sections A, B, C. Itis understood that braided wires can loop from A to C to A. However,segment 1751 is not so limited and braided wires can also loop from A toB to A. In other examples, braided wires can loop from A to B to A to Cto A. In other examples, braided wires can loop from A to C, as well asany combination of these various braided wire loop configurations. Insome examples, at least one braid wire of tip 1751 can be twisted justproximal of ring 1754 to hold ring 1754 in place.

Turning to FIG. 15B, a close-up of tip 1751 is shown in the expanded,inverted funnel-shape configuration. Here, it can be seen that segment1752 has been inverted and expanded as ring 1754 has been translatedproximally, as in previous example distal tips of this disclosure. FIG.15C is a similar view of FIG. 15B, but with the mandrel and/or dilatorremoved and leaving tip 1751 alone in the expanded, invertedfunnel-shape configuration.

FIG. 16A is a close-up view of section A of FIG. 15A showing braidedwires as previously described. FIG. 16B is a close-up view of section Bof FIG. 15A showing braided density or PPI change as previouslydescribed. FIG. 16C is a close-up view of section C of FIG. 15A showingbraided wires looped around pull ring as previously described. FIG. 16Dis a close-up cross-section view of section C of FIG. 15A along centerline with an example dilator 1770 coupled with ring 1754. As shown,dilator 1770 has circumferential ribs to grip pull ring 1754. FIG. 16Eis a close-up cross-section view of section C of FIG. 15A along centerline with another example dilator 1770 coupled with ring 1754, wherebydilator 1770 includes abutment features that fold distally to aid radialcompression to squeeze through ring 1754 after reaching a predeterminedforce. FIG. 16F is a close-up perspective view of section C of FIG. 15Ashowing braided wires looped and coupled with ring 1754, as previouslydescribed. The filaments in the present example can extend proximal todistal and can be looped back at the distal end. Ring 1754 can bethreaded through the looped ends such that when inverted the loopedfilaments rotate about ring 1754 to invert the outward face to faceradially inwardly and thereby form a distal facing funnel, as shown.

Visibility during deployment of any of the herein disclosed cathetersystems can be aided by adding alloying elements (such as palladium,platinum, gold, etc.), by the application of a radiopaque compound, orthrough the placement of radiopaque markers on one or more of thecatheters and devices. Suitable practices are frequently used inconnection with other devices and implants and are well known in theart. For example, a radiopaque compound can be incorporated on a covercan be incorporated in the distal tip, or one or more radiopaque markerscan be added at, on, and/or adjacent the distal end of the tip.Additionally, one or more of the braid wires may include DFT wirecomprising a platinum core (for radiopacity) with NiTi outer layer. Withsuch markers, the physician will be able to visually confirm that themouth has fully inverted and expanded to the vessel wall.

The aspiration source used in the catheter systems of this disclosurecan be a manual syringe or a small-displacement vacuum pump andaspiration directed to the distal tip of any of the herein disclosedcatheter systems. Effective aspiration can be accomplished by thesealing action of the inverted, funnel shape of the distal tip with thevessel walls, the interior walls of an outer catheter, and/or throughthe use of a flow restrictor/seal. In some instances, however,dislodging or fully retrieving a clot with any of the heretoforecatheter systems using aspiration alone is not possible. In thisrespect, it is contemplated that a thrombectomy device can be used withthe catheter systems of this disclosure and can be any of a number ofcommercially available products which can be supplied with or separatefrom the aspirating clot retrieval catheter. Using a thrombectomy devicein conjunction with an expanding mouth catheter system of thisdisclosure has several benefits to increase the likelihood of first-passsuccess. The thrombectomy device can support the lumen of the vesselduring aspiration such that it will be less likely to collapse undernegative pressure, and the thrombectomy device will hold the clottogether should the clot comprise an array of stiff and soft portionsthat may otherwise fragment. The thrombectomy device can also allow theuser to pinch a clot that otherwise would not fully enter the lumen ofthe clot retrieval catheter between the catheter tip and thrombectomydevice. A pinched clot will be less likely to dislodge from the clotretrieval catheter as the clot retrieval catheter, clot, andthrombectomy device are retracted as one through the vasculature andouter catheter.

FIG. 17 is a flow diagram each comprising method steps for performing aprocedure with one system of this disclosure. The method steps can beimplemented by any of the example systems, devices, and/or apparatusdescribed herein or by a means that would be known to one of ordinaryskill in the art.

Referring the method 1700 outlined in FIG. 17 , step 1710 includesadvancing any catheter of this disclosure to a target site. Step 1720includes retracting, by a dilator at least partially within a lumen ofthe catheter and preferably removing the dilator to maximize aspirationflow rate and force on a clot that is retracted into the catheter, adistal tip of the catheter, causing the distal tip to expand and invertto a funnel shape.

In some examples of method 1700, the dilator can be withdrawn andaspiration can then be applied through the catheter, depending on howthe user has deployed the flow restrictions and/or seals, to stimulatethe clot into the mouth of the catheter. If aspiration alone isinsufficient to dislodge and capture the thrombus or if additional gripon the clot is desired during initial aspiration and dislodgement, amicrocatheter with a mechanical thrombectomy clot retrieval device canbe advanced to the target. The mechanical thrombectomy device can thenbe deployed to capture the clot using any method commonly known in theart. Aspiration can continue during the entirety of this step to preventblood reflux and maintain a tight grip on the clot, or at intervalschosen by the user. In some examples, aspiration and pulling of the clotwith a stent retriever may be optimal to increase the chances of firstpass success.

In some examples of method 1700, the captured clot and clot retrievalcatheter can be withdrawn from the patient or the clot retrievalcatheter can be left in place to maintain access as the mechanicalthrombectomy clot retrieval device is withdrawn with the clot from thepatient. If the clot is observed in the aspiration source and/orthrombectomy device and flow is not blocked in the clot retrievalcatheter, this step can also involve carefully injecting contrast underlow pressure through the system using known techniques to determine ifthe vessel is patent. If the vessel is patent, the clot retrievalcatheter can be removed. If a blockage remains, additional passes ofaspiration, thrombectomy or a combination of these may be repeated untilthe vessel is patent.

The disclosure is not necessarily limited to the examples described,which can be varied in construction and detail. The terms “distal” and“proximal” are used throughout the preceding description and are meantto refer to a positions and directions relative to a treating physicianor user. As such, “distal” or “distally” refer to a position distant toor a direction away from the physician. Similarly, “proximal” or“proximally” refer to a position near to or a direction towards thephysician. Furthermore, the singular forms “a”, “an”, and “the” includeplural referents unless the context clearly dictates otherwise.

As used herein, the terms “about” or “approximately” referring to anynumerical values or ranges indicate a suitable dimensional tolerancethat allows the part or collection of components to function for itsintended purpose as described herein. More specifically, “about” or“approximately” may refer to the range of values±20% of the recitedvalue, e.g. “about 90%” may refer to the range of values from 71% to99%.

In describing example embodiments, terminology has been resorted to forthe sake of clarity. It is intended that each term contemplates itsbroadest meaning as understood by those skilled in the art and includesall technical equivalents that operate in a similar manner to accomplisha similar purpose without departing from the scope and spirit of thedisclosure. It is also to be understood that the mention of one or moresteps of a method does not preclude the presence of additional methodsteps or intervening method steps between those steps expresslyidentified. Some steps of a method can be performed in a different orderthan those described herein without departing from the scope of thedisclosed technology. Similarly, it is also to be understood that someof the method steps may be omitted.

The mention of one or more components in a device or system does notpreclude the presence of additional components or intervening componentsbetween those components expressly identified. For clarity andconciseness, not all possible combinations have been listed, and suchmodifications are often apparent to those of skill in the art and areintended to be within the scope of the claims which follow.

What is claimed is:
 1. A catheter system actuatable to a deployed state,comprising: a catheter body comprising a lumen; and a dilator positionedat least partially within the lumen, a distal end of the dilatorreleasably connected to a distal tip of the catheter body, the dilatorbeing retractable to expand and invert the distal tip such that thedistal tip forms a funnel shape in the deployed state; the distal tipcomprising: a proximal segment; and a distal segment extending from theproximal segment, the distal segment being substantially flexible, thedistal segment further comprising a proximal end and a distal end, theproximal end comprising a first mating surface; a pull ring adjacent tothe distal end of the distal segment, the pull ring comprising a secondmating surface, wherein the first mating surface and the second matingsurface are configured to snap lock together.
 2. The system of claim 1,wherein a midpoint of the distal segment in a collapsed statetransitions to being a distalmost atraumatic end of the funnel shape inthe deployed state distal of the catheter body.
 3. The system of claim1, the distal segment in a collapsed state being substantially tubularand in the deployed state comprising the funnel shape, an air cushionformed by the funnel shape between the distal end of the distal segmentand the pull ring.
 4. The system of claim 1, the distal segment dividedinto a proximal braid portion and a distal spiral portion.
 5. The systemof claim 1, the dilator comprising a proximal dilator segment; a distaldilator segment distal of the proximal dilator segment comprising adiameter greater than a diameter of the proximal dilator segment, thedistal dilator segment comprising a contact element extended radiallyoutward from the distal dilator segment and configured to contact andtranslate proximally the pull ring until the pull ring is aligned at oradjacent to the proximal end of the distal segment extended from theproximal segment of the distal tip.
 6. The system of claim 5, thecontact element comprising an interference fit with the distal end ofthe distal tip of the catheter body.
 7. The system of claim 5, thedistal segment of the dilator comprising a greatest diameter at thecontact element and decreases from the contact element to the distal endof the distal segment.
 8. The system of claim 5, the distal segment ofthe dilator comprising a greatest diameter at the contact element andtapers from the contact element to a junction between the proximalsegment of the dilator and the distal segment of the dilator.
 9. Thesystem of claim 5, the proximal segment of the dilator being highlyflexible or substantially more flexible than the distal segment of thedilator.
 10. The system of claim 9, further comprising: a substantiallyflexible segment extending distally of the stiffer distal segment, thesubstantially flexible segment being a short nose.
 11. The system ofclaim 5, the proximal segment of the dilator comprising a fiberreinforcement system to negate elongation.
 12. The system of claim 1,wherein the proximal end of the distal tip and the pull ring are lockedtogether in the deployed state.
 13. The system of claim 1, the distaltip being configured to first expand to a substantially conical shapebefore inverting to form the funnel shape.
 14. The system of claim 1,the distal tip comprising a braid comprising proximal, middle, anddistal portions, wherein the braid comprises filaments extended from theproximal portion to the distal portion in a helical configuration,wherein the distal portion comprises sufficient radial force to push theproximal portion radially outwardly while being configured toaccommodate various vessel sizes in an atraumatic manner.
 15. A methodof inverting an expansile catheter in a blood vessel, comprising:advancing the catheter to a target site; retracting, by a dilator atleast partially within a lumen of the catheter, a pull ring approximatea distal tip of the catheter, causing the distal tip to expand andinvert to a funnel shape, the pull ring and a proximal end of the distaltip each comprising mating surfaces configured to snap lock together.16. The method of claim 15, further comprising: restricting, by thefunnel shape, flow in the blood vessel.
 17. The method of claim 15,further comprising: withdrawing the dilator from the catheter;aspirating through the catheter to stimulate a thrombus into a mouth ofthe funnel shape; and withdrawing the catheter with the thrombus from apatient.
 18. The method of claim 15, further comprising: capturing anocclusive thrombus with a mechanical thrombectomy device; andwithdrawing the mechanical thrombectomy device into the funnel shape ofthe catheter.